2) (3 points) A doctor prescribes 13 milligrams of a therapeutic drug that has decayed to 25% of its original quantity after 6 hours (ie. after 6 hours, only 25% remains). Assume the quantity of the drug is modeled by an exponential equation. 3.) Give a function that describes the quantity of the drug (in milligrams) after 15 hours. b) How long until only 5% of the drug remains? Please use a calculator to get the nal answer and round down to two decimal places